Digital video coding standards, like MPEG-1, MPEG-2, and MPEG-4 have been the engines behind the commercial success of digital video compression and are found in many application scenarios such as broadcast, satellite, cable and terrestrial transmission channels, wireless real-time conversational services, internet video streaming and storage formats (like DVD, and digital camcorders).
MPEG-2 is the current video coding standard of choice of the broadcast video industry, operating at bit rates from around 3 to 10 Mbps, and provides inter-operable ways of representing audio visual content commonly used in digital media and in digital transmission. Also, MPEG-4 extends this to many more application areas through features including its extended bit rate range, scalability and error resilience.
The emerging H.264 standard presents a rich collection of state-of-the-art video coding capabilities that can provide inter-operable video broadcast or communication with degrees of capability that far surpass those of prior standards. The H.264 standard was jointly developed by the Video Coding Experts Group (VCEG) of the ITU-T and the Moving Picture Experts Group (MPEG) of ISO/IEC to primarily achieve enhanced coding efficiency and to accommodate a wider variety of bandwidth requirements and picture formats. It uses state-of-the-art coding tools and provides enhanced coding efficiency for a wide range of applications, including video telephony, video conferencing, TV, storage (DVD and/or hard disk based, especially high-definition DVD), streaming video, digital video authoring, digital cinema, and many other applications.
Conversion of existing MPEG-2/MPEG-4 content into H.264 format would open new possibilities in the areas of storage and broadcast, such as squeezing more TV programs into a given channel bandwidth, delivering quality video over bandwidth-constrained networks and fitting a high definition movie feature onto a standard DVD. Since MPEG-4 standard is a logical extension of MPEG-2, transcoding of MPEG-2 format content to MPEG-4 format is fairly straight forward. However, H.264 is a substantially more complex standard than MPEG-2/MPEG-4. Hence trans-coding a MPEG-2/MPEG-4 bit stream into H.264 format would involve a high degree of complexity.